<!DOCTYPE HTML>
<html>
<head>
  <title>Timeline | Groups ordering</title>

  <style>
    body, html {
      font-family: arial, sans-serif;
      font-size: 11pt;
    }

    #visualization {
      box-sizing: border-box;
      width: 100%;
      height: 300px;
    }
  </style>

  <script src="../../../dist/vis.js"></script>
  <link href="../../../dist/vis-timeline-graph2d.min.css" rel="stylesheet" type="text/css" />
  
</head>
<body>
<p>
  This example demonstrates custom ordering of groups.
</p>
<div id="visualization"></div>

<script>
  var groups = new vis.DataSet([
    {id: 0, content: 'First', value: 1},
    {id: 1, content: 'Third', value: 3},
    {id: 2, content: 'Second', value: 2}
  ]);

  // create a dataset with items
  // note that months are zero-based in the JavaScript Date object, so month 3 is April
  var items = new vis.DataSet([
    {id: 0, group: 0, content: 'item 0', start: new Date(2014, 3, 17), end: new Date(2014, 3, 21)},
    {id: 1, group: 0, content: 'item 1', start: new Date(2014, 3, 19), end: new Date(2014, 3, 20)},
    {id: 2, group: 1, content: 'item 2', start: new Date(2014, 3, 16), end: new Date(2014, 3, 24)},
    {id: 3, group: 1, content: 'item 3', start: new Date(2014, 3, 23), end: new Date(2014, 3, 24)},
    {id: 4, group: 1, content: 'item 4', start: new Date(2014, 3, 22), end: new Date(2014, 3, 26)},
    {id: 5, group: 2, content: 'item 5', start: new Date(2014, 3, 24), end: new Date(2014, 3, 27)}
  ]);

  // create visualization
  var container = document.getElementById('visualization');
  var options = {
    // option groupOrder can be a property name or a sort function
    // the sort function must compare two groups and return a value
    //     > 0 when a > b
    //     < 0 when a < b
    //       0 when a == b
    groupOrder: function (a, b) {
      return a.value - b.value;
    },
    editable: true
  };

  var timeline = new vis.Timeline(container);
  timeline.setOptions(options);
  timeline.setGroups(groups);
  timeline.setItems(items);

</script>
</body>
</html>